| 摘要 |
<p>A sensor (20) having both near infra-red and extended blue-green sensitivity, and a photocathode (26) for such a sensor, includes a GaAs active layer (56) configured to provide a greater spectral response in the visible portion of the spectrum while still providing an effective response in the near infra-red portion of the spectrum, and an AlGaAs window layer (58) configured to transmit a greater portion of the visible spectrum to the active layer. Consequently, the sensor (and photocathode) provide a spectral response in the near infra-red portion of the spectrum, like conventional Gen 3 sensors and photocathodes, and also provides a strong spectral response in the visible portion of the spectrum from the deep red wavelengths to about the blue-green transition wavelengths. As a result, a sensor using such a photocathode can respond to or image both near infra-red wavelengths, as well as responding to or imaging a major portion of the visible spectrum. The inventive sensor can thus replace two conventional sensors (visible light and near infra-red light sensors) with a single sensor, which single sensor is also free of transition difficulties encountered with two conventional sensors during periods of changing illumination.</p> |
